realpath

Get absolute path of a file

$ realpath [file.txt]

$ realpath [symlink]

$ realpath -s [symlink]

$ realpath --relative-to=[/base/path] [/full/path/file]

$ realpath --relative-base=[/base] [/base/subdir/file]

$ realpath [file1] [file2] [file3]

$ realpath -q [file]

realpath [options] file...

realpath prints the resolved absolute pathname of files. It expands all symbolic links, resolves references to /./, /../, and removes extra slashes to produce a canonical path.
The tool is useful in shell scripts when you need the absolute path of a file regardless of how it was specified (relative path, symlink, etc.). It can also compute relative paths between two locations.
realpath is part of GNU coreutils and provides similar functionality to the readlink command with -f flag.

-e, --canonicalize-existing

All path components must exist.

No path component needs to exist.

Resolve .. before symlinks.

Resolve symlinks first (default).

Don't resolve symlinks.

Print path relative to directory.

Print relative path if below base.

Suppress error messages.

End each output line with NUL.

Behavior may differ between GNU coreutils and BSD versions. Without -e, path may not exist. Relative path options require careful base directory specification.

realpath as a standalone command became part of GNU coreutils in version 8.15 (released 2012). Prior to this, the realpath() function existed in C libraries, and the readlink command provided similar functionality. The standalone command simplified common shell scripting tasks.

readlink(1), dirname(1), basename(1), pwd(1)